1. Field of the Invention
The present invention relates to an electronic calculating device and an operation method of the electronic calculating device. More particularly, the present invention relates to an electronic abacus calculator and an operation method thereof.
2. Description of Related Art
Currently, calculating tools including abaci, calculators, and computers are used in numerical calculation. China Patent No. 01210572.4 discloses an “Electronic Abacus Calculator”, which includes a case, “+”, “−”, “C”, and “=” keys placed on the right side of the case, “×” “+” keys, a “” beeping key, and an ON/OFF key placed on the left side of the case, five numeral keys placed at the central portion of the case, an LCD display at a top left portion, and a solar battery at a top right portion. The numeral keys indicates “5”, “1”, “2”, “3”, and “4” sequentially, and “Decimal Fraction”, “Ones”, “Thousands”, and “Millions” are marked on the “1” key to indicate the decimal fractions and integral digits. The function keys, the numeral keys, and the display are integrated with an integrated circuit. The conventional “electronic abacus calculator” has the following disadvantages. (1) In the subtraction operation, both the “−” and “=” keys must be engaged, so more operation steps are required. (2) The decimal digits are fixed, and cannot be floated. (3) The continuous four fundamental mixed operations of addition, subtraction, multiplication, and division cannot be carried out. (4) The result of the calculation cannot be temporarily memorized. And (5) decimal digits displayed in the result of calculation cannot be controlled or selected.